Seaweed Extract Foliar Application on Growth, Biochemical Traits, and Stilbene Production in Peanut Shoot-Derived...

The limited natural occurrence of stilbenes, a valuable compound, in sources such as peanuts restricts their full exploitation for health benefits. To address this challenge, we explored the novel use of Sargassum vulgare liquid extract (SLE) as a biostimulant to enhance stilbene production in peanut plants shoots. While seaweed extracts have been previously studied for general crop improvement, this work uniquely demonstrates a genotype-specific and concentration-dependent enhancement of piceatannol levels. Three peanut cultivars: 'Trabelsia' (AraT), 'Chanfakhi' (AraC), and 'American' (AraA) treated with six foliar SLE concentrations (0%, 0.5%, 1%, 2%, 4%, 8%) weekly for 7 weeks, starting 21 days after germination. Significant improvements (p < 0.05) in plant growth, pigment content, and yield were observed, with the highest biomass in AraT at 8% SLE and the highest pod production in AraC and AraA at 1-2%. Polyphenol and flavonoid content peaked under SLE at 8% AraC and 1%, respectively. Most notably, piceatannol content in AraA increased threefold (30.11 ± 2.6 µg/g DW) with 8% SLE, while resveratrol and piceid levels showed limited changes across treatments. These findings highlight the innovative use of S. vulgare extract as a sustainable elicitor for targeted piceatannol enrichment in peanut byproducts, opening avenues for their valorisation in nutraceutical or pharmaceutical applications.